(1) TECHNICAL FIELD
The subject invention relates to a hydraulic vibratory compaction roller adapted to be permanently and pivotally connected to the back of a vehicle.
(2) DESCRIPTION OF THE PRIOR ART
Compaction rollers are well known in the art and are employed, for example, by construction contractors who are involved in digging operations. For instance, when laying sewer pipes, the construction contractors are required to compact the soil tightly when back filling trenches. To accomplish this, contractors employ large independently driven roller machines with large drum rollers located on the front, similar to the type used to compact asphalt during road paving. This invention, however, relates to tow type vibratory compaction rollers adapted to be towed behind bulldozers, or the like, to compact the back fill in the trenches.
For example, U.S. Pat. No. 3,623,407 issued to Dresher on Nov. 30, 1971 discloses a vibratory compaction roller which includes a hitch and a source of hydraulic power mounted to the back of a bulldozer. The compaction roller is permanently attached to the back of the bulldozer and includes a frame in the form of a yoke and a tow bar. A drum is rotatably mounted in the arm of the yoke. Although the roller is permanently attached to the back of the bulldozer, the Dresher '407 patent does not disclose a roller lift means for raising and lowering the roller nor a first and second hydraulic pump for supplying hydraulic power to both the hydraulic cylinder or the roller lift means and the hydraulic vibration producing means on the roller.
Compaction rollers adapted to be towed behind vehicles and including roller lift means are also known in the art and shown in U.S. Pat. No. 4,378,052 issued to Anderson on Mar. 29, 1983. The Anderson '052 patent discloses an articulated tractor attachment with roller including a three part hitch and a hydraulic cylinder for raising and lowering the roller. However, the Anderson '052 patent does not disclose any means for vibrating the roller.
Detachable tow type compaction rollers are difficult to hitch to and from machinery and this can also be time consuming. In addition, detachable tow type compaction rollers are presently manufactured with vibration producing motors for vibrating the drum rollers which aid in the compaction process. These motors increase the cost of the detachable tow type compaction rollers.